A positive electrode material and a secondary ion battery containing the same

Abstract

The application provides a positive electrode material and a secondary ion battery containing the positive electrode material. The positive electrode material comprises at least: a positive electrode active substance, wherein the positive electrode active substance comprises a first active substance and a carrier; the first active substance is selected from alkali metal halide or alkali metal sulfite, alkaline earth metal halide or alkaline earth metal sulfite, halide of aluminum or sulfite of aluminum, or halide of zinc or sulfite of zinc; and the carrier has a low-dimensional structure; the carrier is selected from a template and / or a second active substance. The application adopts the first active substance to prepare the positive electrode material, and has high universality. Meanwhile, the preparation method of the application is simple and convenient in operation, and low in production cost.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to a positive electrode material and a secondary ion battery containing the positive electrode material. Background Technology

[0002] Current lithium-ion battery development meets the needs of applications ranging from 3C electronics, power tools and automobiles to grid-scale energy storage. Lithium-ion battery systems based on lithium iron phosphate, ternary lithium, lithium cobalt oxide, and lithium-rich manganese-based cathode materials satisfy most current application scenarios. However, in the foreseeable future, the abundance of lithium and the cost of existing electrode materials will significantly limit the development of lithium-ion batteries. Therefore, there is an urgent need to develop high-performance, low-cost electrode materials to meet the ever-increasing energy demands. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a cathode material and a secondary ion battery containing the cathode material. This invention prepares a cathode material with high specific energy and high voltage by reducing the dimensionality of the cathode material or changing its crystal morphology, particularly preparing a cathode material containing halide salts or sulfites. This invention also constructs a stable charge-discharge secondary ion battery system, and the secondary ion battery of this invention exhibits long-term stable charge-discharge performance.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] A positive electrode material, the positive electrode material comprising at least: a positive electrode active material, the positive electrode active material comprising a first active material and a carrier.

[0006] The first active substance is selected from alkali metal halide salts or alkali metal sulfites, alkaline earth metal halide salts or alkaline earth metal sulfites, aluminum halides or aluminum sulfites, or zinc halides or zinc sulfites.

[0007] The carrier has a low-dimensional structure; the carrier is selected from templates and / or a second active substance.

[0008] According to the present invention, in the positive electrode material, the first active material can be uniformly distributed on the support or in the low-dimensional structure of the support.

[0009] According to the present invention, the low-dimensional structure includes at least one of zero-dimensional structure, one-dimensional structure, two-dimensional structure, three-dimensional structure, and multi-level structure.

[0010] According to the present invention, the low-dimensional structure may include a crystalline structure or an amorphous structure.

[0011] In this invention, the low-dimensional structure refers to a structure whose smallest structural unit has a size of no more than 1 μm in at least one dimension, for example, 1 nm-100 nm.

[0012] According to the present invention, the template has a zero-dimensional structure, a one-dimensional structure, a two-dimensional structure, a three-dimensional structure, or a multi-level structure. The multi-level structure mentioned in the present invention refers to a structure including one of the following: a zero-dimensional structure, a one-dimensional structure, a two-dimensional structure, or a three-dimensional structure.

[0013] According to the present invention, the second active substance has a zero-dimensional structure, a one-dimensional structure, a two-dimensional structure, a three-dimensional structure, or a multi-level structure.

[0014] For example, the zero-dimensional structure template is selected from at least one of quantum dots, nanoparticles, etc.

[0015] For example, the one-dimensional structural template is selected from at least one of nanowires, nanotubes, nanoribbons, etc.

[0016] For example, the two-dimensional structure template is selected from at least one nanosheet, including but not limited to graphene, MXene, TiO2 nanosheets, etc.

[0017] For example, the multi-level structure template is, for instance, a material that has a low-dimensional structure itself or is composed of a material that has a low-dimensional structure, selected from, but not limited to, at least one of activated carbon, metal-organic framework materials, covalent organic framework materials, alumina templates, metal foams, and microfabrication to prepare micro- and nanostructures.

[0018] For example, the three-dimensional structure template is prepared by at least one of the zero-dimensional structure template, one-dimensional structure template, and two-dimensional structure template, for example by stacking, assembly, automatic coating, or solution self-aggregation.

[0019] It should be noted that the present invention reduces the dimensionality of the first active material or disrupts or changes its crystal morphology through the carrier, thereby obtaining a cathode material with high specific energy and high voltage, especially a cathode material containing halogen salts or sulfites.

[0020] According to the present invention, the cathode material is at least partially low-dimensional in structure.

[0021] In this embodiment, at least a portion of the halide salts or sulfites in the positive electrode material exhibit a low-dimensional structure. According to the present invention, the support is preferably selected from templates, and optionally includes or excludes a second active material.

[0022] According to the present invention, the second active material is selected from any of the positive electrode active materials known in the art, such as LiMn2O4, MnO2, Li3V2(PO4)3, LiFePO4, ternary materials or Prussian blue active materials.

[0023] Preferably, the second active material comprises nanoparticles, and further, the nanoparticles may form microspheres. It should be noted that, in this invention, a microsphere refers to a microsphere structure composed of multiple nanoparticles with a size reaching the micrometer scale. For example, the particle size of the microsphere is not less than 0.1 μm, such as 0.1-100 μm, 0.1-10 μm, or 0.1-1 μm.

[0024] It should be noted that the present invention does not specifically limit the form of the template. The form of the template can be selected from any form such as dispersion, foam, assembled membrane, powder, slurry, gel, etc., for example, foam. In the present invention, the template being in gel form means that a gel-shaped carrier is obtained by adding a known gelling substance (such as a polymer or small organic molecule), and then the first active substance is adsorbed and deposited therein to obtain the above-mentioned positive electrode material.

[0025] According to the present invention, the alkali metal halide salt is selected from at least one of lithium chloride, lithium bromide, lithium iodide, sodium chloride, sodium bromide, sodium iodide, potassium chloride, potassium bromide, and potassium iodide.

[0026] According to the present invention, the alkali metal sulfite is selected from at least one of lithium sulfite, sodium sulfite, and potassium sulfite.

[0027] According to the present invention, the alkaline earth metal halide salt is selected from at least one of magnesium chloride, magnesium bromide, magnesium iodide, calcium chloride, calcium bromide, and calcium iodide.

[0028] According to the present invention, the alkaline earth metal sulfite is selected from magnesium sulfite and / or calcium sulfite.

[0029] According to the present invention, the aluminum halide is selected from at least one of aluminum chloride, aluminum bromide, and aluminum iodide.

[0030] According to the present invention, the aluminum sulfite is selected from aluminum sulfite.

[0031] According to the present invention, the zinc halide is selected from at least one of zinc chloride, zinc bromide, zinc iodide, zinc sulfite, etc.

[0032] According to the present invention, the zinc sulfite is selected from zinc sulfite.

[0033] According to the present invention, in the positive electrode material, the first active material accounts for 1-99% of the total mass of the positive electrode material, preferably 5-90%, for example 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90%.

[0034] According to the present invention, in the positive electrode material, the carrier accounts for 0.1-99% of the total mass of the positive electrode material, preferably 1-95%, and even more preferably 5-90%, for example 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90%.

[0035] It should be noted that the present invention does not specifically limit the mass ratio of the template and the second active substance in the carrier. The carrier can be obtained by using a mass ratio known in the art, as long as the above-mentioned positive electrode material can be obtained. For example, in the carrier, the mass ratio of the template and the second active substance is (0.1-1):(0-10), such as (0.1-1):0.1, (0.1-1):0.2, (0.1-1):0.3, (0.1-1):0.4, (0.1-1):0.5, (0.1-1):0.6, (0.1-1):0.7, (0.1-1):0.8, (0.1-1):0.9, (0.1-1):1, (0.1-1):2, (0.1-1):3, (0.1-1):4, (0.1-1):5, (0.1-1):6, (0.1-1):7, (0.1-1):8, (0.1-1):8, (0.1-1):10.

[0036] According to the present invention, the first active material has a low-dimensional structure or a micro / nanocrystalline structure.

[0037] According to the present invention, in the positive electrode material, when the first active material is distributed in the low-dimensional structure, the first active material has a low-dimensional structure, and the low-dimensional structure has the meaning as described above.

[0038] For example, the first active material in the cathode material is selected from KI, wherein KI has a low-dimensional structure, such as a two-dimensional crystal structure with a lattice spacing of 0.353 nm, corresponding to a 200 crystal plane.

[0039] According to the present invention, when the first active material is distributed on the carrier, the first active material constitutes micro / nano crystals. The present invention does not specifically limit the mass content of the micro / nano crystals in the first active material; for example, it may be 0-10%, or 0-5%, or even 0-1%.

[0040] Preferably, the particle size range of the micro / nano crystals is 0.1-5μm, more preferably 0.5-5μm, for example 1μm, 2μm, 3μm, 4μm, 5μm.

[0041] The inventors have discovered that the lower the content of micro / nano crystallites in the cathode material, the better the battery performance. Therefore, according to a preferred embodiment of the present invention, the content of low-dimensional structures in the first active material is higher than the content of micro / nano crystallites.

[0042] It should be noted that during battery charging and discharging, the low-dimensional structures and / or micro / nano crystals in the first active material will partially dissolve in the electrolyte, or precipitate from the electrolyte and reform low-dimensional structures and / or micro / nano crystals on the carrier. As the battery charging and discharging process proceeds, the micro / nano crystals will dissolve into the electrolyte as a supplement, and then deposit on the carrier to form low-dimensional active materials, thereby ensuring stable battery operation.

[0043] According to the present invention, the cathode material can also be processed by methods known in the art, such as carbonization, elution and other known methods, to obtain a cathode material that almost does not contain a template.

[0044] According to an exemplary embodiment of the present invention, the positive electrode material comprises a first active material and a support; the support comprises a second active material; the first active material and the second active material are composited to form the positive electrode material. For example, the first active material fills the pores of nanoparticles or microspheres of the second active material to form the positive electrode material.

[0045] The present invention also provides a method for preparing the above-mentioned cathode material, the method comprising: mixing the carrier and the first active substance, and then compounding them to obtain the cathode material of the present invention, wherein the carrier and the first active substance have the meanings described above.

[0046] Preferably, when the carrier is selected from a template and optionally includes or excludes a second active substance, the mixing comprises:

[0047] First, mix the template and the first active substance, then add the second active substance; or,

[0048] First, mix the template and the second active substance, then add the first active substance; or,

[0049] First, mix the second active substance and the first active substance, and then add the template.

[0050] According to the present invention, the preparation method further includes, after composite, the cathode material is optionally treated by any one of the following methods: high-temperature carbonization or elution.

[0051] According to the present invention, in the preparation method, the carrier can be pretreated to obtain the desired form. Preferably, the carrier is pretreated to obtain any form such as dispersion, foam, assembled film, powder, slurry, etc., for example, foam.

[0052] According to the present invention, the high-temperature carbonization specifically includes: carbonizing the positive electrode material at a high temperature of 400-1000°C, for example, carbonizing at a high temperature of 700°C. Exemplarily, the carbonization time is 1-10 hours, for example, 4 hours.

[0053] According to an exemplary embodiment of the present invention, the method for preparing the positive electrode material includes the following steps:

[0054] (1) The carrier is ultrasonically dispersed in water to obtain a mixture, and the mixture is frozen to obtain foam;

[0055] (2) After compacting the foam from step (1), add a solution containing the first active substance to the compacted foam, and let it dry to obtain the cathode material precursor.

[0056] (3) The cathode material precursor obtained in step (2) is carbonized at high temperature to obtain the above cathode material.

[0057] According to the present invention, the carrier and the first active substance have the definitions described above.

[0058] According to the present invention, the mass concentration of the carrier in the mixture is 1-100 mg / g, for example, 10 mg / g.

[0059] According to the present invention, the freezing includes: a first freezing and a second freezing.

[0060] Preferably, the conditions for the first freezing include freezing at -70 to -100°C for at least 1 hour, preferably 1 to 10 hours, for example freezing at -80°C for 2 hours.

[0061] Preferably, the conditions for the second freezing include: freeze-drying at -40 to -70°C for at least 10 hours, preferably 10 to 100 hours, for example, freeze-drying at -60°C for 40 hours.

[0062] Preferably, step (2) may optionally include slicing the compacted foam. In this invention, slicing refers to cutting the compacted foam into arbitrary sizes to meet the application requirements of the cathode material. For example, the sizes can be circular, square, or irregular in shape. For instance, slicing the compacted foam yields circular slices with a diameter of 11 mm.

[0063] Preferably, the solution containing the first active substance comprises the first active substance and a solvent. Preferably, the solvent is selected from volatile solvents, such as methanol, ethanol, acetone, and dichloromethane. Exemplarily, the solution containing the first active substance is selected from potassium iodide methanol solution.

[0064] Preferably, in the solution containing the first active substance, the mass concentration of the first active substance is 0.01-10 g / mL, for example, 0.1 g / mL.

[0065] According to the present invention, the elution specifically includes: adding the positive electrode material to the eluent to remove all or part of the template.

[0066] Preferably, the eluent is selected from concentrated acids or concentrated bases. For example, the concentrated acid is selected from concentrated hydrochloric acid.

[0067] According to an exemplary embodiment of the present invention, the method for preparing the positive electrode material includes the following steps:

[0068] (1) The first active substance and the carrier are ultrasonically dispersed in a solvent to obtain a mixture, which is then dried to obtain a solid material;

[0069] (2) Add the solid material from step (1) to the eluent to remove all or part of the template and obtain an intermediate;

[0070] (3) After the intermediate in step (2) is dried, the cathode material is obtained.

[0071] Preferably, the drying can be carried out using methods known in the art, such as vacuum drying at 90°C for 6 hours.

[0072] The present invention also provides a modified cathode material, which is obtained by eluting the template in the cathode material described in the present invention, wherein the template and elution have the meanings described above.

[0073] According to the present invention, the modified cathode material contains almost no template.

[0074] This invention also provides the application of the above-mentioned cathode material in secondary ion batteries. Preferably, the secondary ion battery is selected from organic secondary ion batteries and organic / water hybrid secondary ion batteries.

[0075] The present invention also provides an organic secondary ion battery, wherein the organic secondary ion battery includes the positive electrode material described above.

[0076] According to the present invention, the organic secondary ion battery further includes a negative electrode material, wherein the negative electrode material is selected from metal and / or carbon negative electrode materials.

[0077] According to the present invention, the metal is selected from at least one of lithium, sodium, potassium, magnesium, calcium, aluminum, and zinc.

[0078] According to the present invention, the carbon anode material can be a commercially available material or a material synthesized in-house. Exemplarily, the carbon anode material is selected from at least one of graphite, hard carbon, soft carbon, etc.

[0079] According to the present invention, the organic secondary ion battery further includes at least one of an electrolyte, a gel electrolyte, or a solid electrolyte, wherein the electrolyte is selected from organic electrolytes.

[0080] According to the present invention, the organic electrolyte comprises an electrolyte and an organic solvent.

[0081] According to the present invention, the electrolyte is selected from, but not limited to, at least one of lithium salt, sodium salt, potassium salt, magnesium salt, calcium salt, aluminum salt, and zinc salt.

[0082] For example, the lithium salt is selected from at least one of lithium sulfate, lithium nitrate, lithium acetate, lithium perchlorate, lithium chloride, lithium difluorosulfonate imine (LiFSI), lithium trifluoromethanesulfonate (LiOTf), lithium bis(trifluoromethanesulfonate)imine, and lithium bis(pentafluoroethylsulfonyl)imine.

[0083] For example, the sodium salt is selected from at least one of sodium perchlorate, sodium acetate, sodium nitrate, sodium chloride, sodium sulfate, sodium difluorosulfonate imine (NaFSI), sodium trifluoromethanesulfonate, sodium bis(trifluoromethanesulfonate)imine, and sodium bis(pentafluoroethylsulfonyl)imino.

[0084] For example, the potassium salt is selected from at least one of potassium nitrate, potassium acetate, potassium sulfate, potassium chloride, potassium difluorosulfonate imine (KFSI), potassium trifluoromethanesulfonate, potassium bis(trifluoromethanesulfonate)imine, and potassium bis(pentafluoroethylsulfonyl)imine.

[0085] For example, the zinc salt is selected from at least one of zinc trifluoromethanesulfonate, zinc sulfate, zinc chloride, zinc acetate, zinc trifluoromethanesulfonate, and zinc bis(trifluoromethanesulfonyl)imide (Zn(TFSI)2).

[0086] For example, the magnesium salt is selected from at least one of magnesium trifluoromethanesulfonate, magnesium sulfate, magnesium chloride, magnesium acetate, and magnesium bis(trifluoromethanesulfonyl)imide.

[0087] According to the present invention, the organic solvent is selected from, but not limited to, at least one of esters, ethers, or nitriles. Exemplarily, the ester is selected from, but not limited to, at least one of methyl acrylate, diethyl carbonate, or ethylene carbonate. Exemplarily, the ether is selected from dimethyl glycol ether. Exemplarily, the nitrile is selected from acetonitrile.

[0088] According to the present invention, the concentration of the electrolyte in the organic electrolyte is 0.01-20 mol / L, preferably 1-10 mol / L, for example 0.01 mol / L, 0.1 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L, 10 mol / L, 11 mol / L, 12 mol / L, 13 mol / L, 14 mol / L, 15 mol / L, 16 mol / L, 17 mol / L, 18 mol / L, 19 mol / L, or 20 mol / L.

[0089] For example, the organic electrolyte is selected from KFSI propylene carbonate solution and KFSI ethylene glycol dimethyl ether solution.

[0090] According to the present invention, the gel electrolyte comprises a first polymer host material and an electrolyte, wherein the electrolyte is selected from the organic electrolyte system.

[0091] Preferably, the first polymer host material is selected from at least one of polyvinyl alcohol (PVA), polyacrylic acid, polyacrylamide, sodium polyacrylate, polyethylene oxide (PEO), polymethyl methacrylate, polyether ether ketone, ethylene glycol acrylonitrile block copolymer, and poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP).

[0092] According to the present invention, the solid electrolyte is selected from at least one of polymer electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0093] According to the present invention, the polymer electrolyte comprises a second polymer matrix and an electrolyte.

[0094] Preferably, the second polymer matrix includes at least one of polyethylene oxide (PEO), polypropylene oxide, polyvinyl alcohol (PVA), polyacrylic acid, polyacrylamide, sodium polyacrylate, polymethyl methacrylate, polyether ether ketone, ethylene glycol acrylonitrile block copolymer, and polyvinylidene fluoride.

[0095] According to the present invention, the inorganic solid electrolyte is selected from at least one of sulfide solid electrolytes and oxide solid electrolytes.

[0096] Preferably, the sulfide solid electrolyte includes a sulfur-lithium ultrafast ion conductor and a sulfide-germanium ore type.

[0097] Preferably, the oxide solid electrolyte is selected from at least one of perovskite type, sodium fast ion conductor type, lithium fast ion conductor type and garnet type.

[0098] Preferably, the composite electrolyte comprises a polymer electrolyte and a second-phase inorganic filler, wherein the polymer electrolyte has the meaning as described above; the second inorganic filler is selected from TiO2, SiO2, Al2O3, ZrO2, MgO, and ZnO. x Metal oxide nanoparticles and at least one of zeolite, montmorillonite, etc.

[0099] According to the present invention, the organic secondary ion battery has good cycle performance and high energy density.

[0100] For example, at 500mA g -1 At a given current density, the organic secondary ion battery retains more than 73% of its capacity after 600 charge-discharge cycles.

[0101] For example, at 100mA g -1 At a given current density, the organic secondary ion battery retains more than 88% of its capacity after 600 charge-discharge cycles.

[0102] The present invention also provides an organic / water hybrid secondary ion battery, wherein the organic / water hybrid secondary ion battery includes the positive electrode material described above.

[0103] According to the present invention, the organic / water hybrid secondary ion battery includes a hybrid electrolyte comprising an electrolyte and a mixed solvent of an organic solvent and water, wherein the electrolyte has the meaning as described above.

[0104] According to the present invention, the mixed solvent of organic solvent and water refers to a mixture of organic solvent and water having the meaning as described above. The present invention does not specifically limit the volume ratio of organic solvent to water in the mixed solvent; any volume ratio known in the art can be used, as long as the mixed solvent can be obtained.

[0105] According to the present invention, the organic / water hybrid secondary ion battery further includes a negative electrode material, wherein the negative electrode material has the meaning as described above.

[0106] Beneficial effects:

[0107] This invention provides a cathode material prepared using a first active material, exhibiting high versatility. Furthermore, the preparation method of this invention is simple, convenient, and has low production costs.

[0108] The secondary ion battery prepared using the cathode material of this invention comprises a first active material consisting of low-dimensional structures and / or micro / nano crystallites, wherein the low-dimensional structures primarily provide capacity. During the charge-discharge process, the low-dimensional structures and / or micro / nano crystallites in the first active material partially dissolve in the electrolyte or precipitate from the electrolyte and reform onto the carrier. As the battery continues to charge and discharge, the micro / nano crystallites dissolve into the electrolyte as a supplement and then deposit on the carrier to form the first active material with a low-dimensional structure, thereby ensuring stable battery operation. Because the first active material of this cathode material has a low molecular weight and a high redox potential, the assembled secondary ion battery exhibits high specific capacity and voltage, thus providing high energy density. Attached Figure Description

[0109] Figure 1 The image shows the microstructure of the KI / rGO / AC cathode in Example 1; where (a) is a scanning electron microscope image; (b)-(d) are energy dispersive spectroscopy (EDS) analyses; and (e)-(f) are transmission electron microscope (TEM) images.

[0110] Figure 2 This is a transmission electron microscope image of the KI / rGO / AC positive electrode in Example 1 after 100 cycles.

[0111] Figure 3 The charge-discharge curves are for the full battery of Example 1.

[0112] Figure 4 The graph shows the cycle performance of the full battery of Example 1 after 800 charge-discharge cycles.

[0113] Figure 5 The graph shows the cycle performance of the half-cell of Example 2 after 600 charge-discharge cycles.

[0114] Figure 6 The graphs show the specific capacity performance of the batteries in Examples 3-5.

[0115] Figure 7 The graph shows the cycle performance of the organic gel battery of Example 7 after 300 charge-discharge cycles.

[0116] Figure 8 The graph shows the cycle performance of the solid-state battery of Example 8 after 800 charge-discharge cycles.

[0117] Figure 9 The graph shows the cycle performance of the half-cell of Example 9 after 200 charge-discharge cycles.

[0118] Figure 10 The images are transmission electron microscope (TEM) images of NaCl solid before (a) and after (b) template removal in Example 10.

[0119] Figure 11 The graph shows the cycle performance of a comparative half-cell after 100 charge-discharge cycles. Detailed Implementation

[0120] The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0121] Unless otherwise specified, the experimental methods used in the following examples are conventional methods; unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0122] Unless otherwise specified, the battery electrical performance tests in the following embodiments were all conducted at 25°C.

[0123] Example 1

[0124] 1. Preparation of positive electrode material: (1) The aqueous dispersion containing graphene oxide (GO, 3 mg / g) and activated carbon (AC, 7 mg / g) was ultrasonically dispersed for 2 hours to obtain a mixed solution. Then, 5 mL of the mixed solution was added to a petri dish with a diameter of 3.5 cm and frozen in a low temperature freezer at -80℃ for 2 hours. After that, it was freeze-dried at -60℃ for 40 hours to obtain GO / AC foam.

[0125] (2) After compacting the GO / AC foam, punch it into a circular sheet with a diameter of 11 mm using a puncher. Then, add 50 μL of potassium iodide methanol solution (0.1 g / mL) to each circular sheet and place it in a fume hood for 48 hours to allow the methanol to evaporate completely.

[0126] (3) The KI / GO / AC sample obtained in step (3) is carbonized at high temperature in a tube furnace at 700℃ for 4 hours to obtain KI / reduced graphene oxide (rGO) / AC, which is the positive electrode sheet.

[0127] Figure 1 The microstructure of the KI / rGO / AC cathode sheet in Example 1 is shown. Figure 1 Scanning electron microscopy and energy dispersive spectroscopy (EDS) images of the middle (ad) layer show that KI is relatively uniformly distributed throughout the foam; from Figure 1 The transmission electron microscope images (e)-(f) show that a portion of the two-dimensional KI crystals were prepared by this method, with a lattice spacing of 0.353 nm, corresponding to the 200 crystal plane.

[0128] The average particle size of the KI micron particles is 2 μm. Elemental analysis shows that the mass fraction of KI in the KI / rGO / AC cathode is 50%.

[0129] 2. Preparation of half-cell: A half-cell was prepared using the above-mentioned KI / rGO / AC material as the positive electrode, potassium metal as the negative electrode, an 8 mol / L potassium difluorosulfonate imine (KFSI) methyl acrylate solution as the electrolyte, and glass fiber as the separator. The mass of the positive electrode active material KI was 3.7 mg. This half-cell was tested at 100 mA g. -1 It still retains 94% of its capacity after 100 charge-discharge cycles at a current density. Figure 2 This is a transmission electron microscope image of the positive electrode after 100 charge-discharge cycles. The image clearly shows the lattice distortion and lattice fringes of the potassium iodide crystal.

[0130] 3. Preparation of full cell: The full cell was prepared using the above KI / rGO / AC material as the positive electrode, potassium-intercalated graphite as the negative electrode, 8 mol / L potassium difluorosulfonate imine (KFSI) methyl acrylate solution as the electrolyte, and glass fiber as the separator. The mass of the positive electrode active material KI was 3.7 mg, and the mass of the negative electrode active material was 3.0 mg.

[0131] Figure 3 For the full cell at 500mA g -1 The charge-discharge curves at the specified current density show that the battery is charged to 4.2V and discharged to 1.5V. The discharge specific capacity of the full battery is 113mAh g. -1 .

[0132] Figure 4 The full cell of Example 1 at 500 mA g -1 The cycle performance graph after 800 charge-discharge cycles at a current density is shown. Figure 4 It can be seen that it still retains 73% of its capacity after 800 charge-discharge cycles.

[0133] Example 2

[0134] 1. Preparation of cathode material: The preparation method of the cathode material in this embodiment is the same as that in Example 1, except that: in step (2), a mixed solution of potassium sulfite and water and methanol (0.1 g / mL) is added dropwise to the circular sheet; in step (3), the K2SO3 / GO / AC sample is carbonized at high temperature in a tube furnace at 500℃ for 4 hours to prepare the K2SO3 / rGO / AC cathode sheet. Elemental analysis shows that the mass fraction of K2SO3 in the K2SO3 / rGO / AC cathode sheet is 45%.

[0135] 2. Preparation of half-cell: The preparation method of this embodiment is the same as that of embodiment 1, except that: the positive electrode is K2SO3 / rGO / AC material, the negative electrode material is metallic potassium, and the electrolyte is 6mol / L KFSI in ethylene glycol dimethyl ether solution, wherein the mass of the active material K2SO3 in the positive electrode material is 2mg.

[0136] Figure 5 The graph shows the cycle performance of the half-cell of Example 2 after 600 charge-discharge cycles at 100 mA g. -1 After 600 charge-discharge cycles at a current density, it still retains 88% of its capacity.

[0137] Example 3: Lithium-ion battery

[0138] 1. Preparation of cathode materials: The preparation method in this embodiment is the same as in Example 1, except that in step (2), methanol solutions of LiCl, LiBr, and LiI are added dropwise to the circular sheet respectively; LiCl / rGO / AC cathode sheets, LiBr / rGO / AC cathode sheets, and LiI / rGO / AC cathode sheets are prepared respectively. The mass fractions of active materials LiCl, LiBr, and LiI in the cathode sheets are 45%, 51%, and 48%, respectively.

[0139] 2. Assemble the battery: Use LiCl / rGO / AC, LiBr / rGO / AC and LiI / rGO / AC positive electrode sheets as positive electrodes, lithium metal as negative electrode, 10mol / L LiFSI propylene carbonate solution as electrolyte, and glass fiber as separator to assemble half cells.

[0140] Figure 6 The values ​​of 'ac' and 'c' represent the three types of half-cells in Example 3 at 100 mA g. -1 The charge-discharge curves at the specified current densities show that the discharge specific capacities of the three half-cells are 315, 153, and 117 mAh g, respectively. -1 .

[0141] Example 4: Sodium-ion battery

[0142] 1. Preparation of cathode materials: The preparation method in this embodiment is the same as in Example 1, except that in step (2), methanol solutions of NaCl, NaBr, and NaI, or a mixture of water and methanol, are added dropwise to the circular sheet respectively; NaCl / rGO / AC cathode sheets, NaBr / rGO / AC cathode sheets, and NaI / rGO / AC cathode sheets are prepared respectively. The mass fractions of active materials NaCl, NaBr, and NaI in the cathode sheets are 52%, 46%, and 48%, respectively.

[0143] 2. Assemble the battery: Using the NaCl / rGO / AC positive electrode, NaBr / rGO / AC positive electrode, and NaI / rGO / AC positive electrode of this embodiment as positive electrodes, metallic sodium as negative electrode, 6mol / L NaFSI propylene carbonate solution as electrolyte, and glass fiber as separator, a half cell is assembled.

[0144] Figure 6 df represents the three types of half-cells in Example 4 at 100mA g. -1 The charge-discharge curves at the specified current densities show that the discharge specific capacities of the three batteries are 116, 156, and 177 mAh g, respectively. -1 .

[0145] Example 5: Zinc-ion battery

[0146] 1. Preparation of cathode materials: The preparation method in this embodiment is the same as in Example 1, except that in step (2), methanol solutions of ZnCl2, ZnBr2, and ZnI2 are added dropwise to the circular sheet respectively; ZnCl2 / rGO / AC cathode sheets, ZnBr2 / rGO / AC cathode sheets, and ZnI2 / rGO / AC cathode sheets are prepared respectively. The mass fractions of the active materials ZnCl2, ZnBr2, and ZnI2 in the cathode sheets are 47%, 46%, and 46%, respectively.

[0147] 2. Assemble the battery: Use the three materials in this embodiment as positive electrodes, metallic sodium as negative electrodes, acetonitrile solution of 2 mol / L Zn(TFSI)2 as electrolyte, and glass fiber as separator to assemble half cells.

[0148] Figure 6 g represents the three types of half-cells in Example 5 at 100 mA g. -1 The charge-discharge curves at the specified current densities show that the discharge specific capacities of the three batteries are 174, 163, and 108 mAh g, respectively. -1 .

[0149] Example 6 Organic / water mixed electrolyte battery

[0150] Using the ZnI / rGO / AC from Example 5 as the positive electrode, metallic zinc as the negative electrode, and a mixed solvent of 2 mol / L Zn(TFSI)2 as the electrolyte (wherein the mixed solvent includes acetonitrile and water in a volume ratio of 1:1), a glass fiber membrane was assembled to obtain a half-cell. This half-cell was tested at 100 mA g. -1 After 1000 charge-discharge cycles at a current density, the capacity retention rate is as high as 87%.

[0151] Example 7 Organic Gel Battery

[0152] Preparation method of organic gel electrolyte: Mix 0.3g of polyethylene oxide (PEO) and 4.5mL of 1.0mol L... -1 The NaFSI propylene carbonate (PC) solution was magnetically stirred for 12 hours and then added to a 6 cm diameter petri dish. After being placed at room temperature for one week, PEO-NaFSI-PC organic gel electrolyte was obtained, which was then crushed into 16 mm diameter sheets for later use.

[0153] Assemble the half-cell: Use NaI / rGO / AC from Example 4 as the positive electrode, metallic sodium as the negative electrode, and PEO-NaFSI-PC as the gel electrolyte to assemble the half-cell.

[0154] Figure 7 The half-cell of Example 7 at 100 mA g -1 The cycle performance graph after 300 charge-discharge cycles at a current density is shown below. Figure 10 It can be seen that 86% of the capacity is still retained after 500 charge-discharge cycles.

[0155] Example 8 Solid-state battery

[0156] Preparation method of solid electrolyte: 0.4 g of poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) was dissolved in 5 mL of dry N,N-dimethylformamide (DMF) and stirred thoroughly for 24 h. Then, 0.1 g of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) was added, and the mixture was stirred for another 24 h to obtain a homogeneous mixed solution. The mixed slurry was quickly poured into a tetrafluoroethylene mold and then slowly dried under vacuum for 48 h. The dried solid electrolyte film PVDF-HFP-LiTFSI was gently peeled off the mold and quickly transferred to a glove box, where it was then formed into sheets with a diameter of 16 mm for later use.

[0157] Battery assembly: Using LiI / rGO / AC from Example 3 as the positive electrode, lithium metal as the negative electrode, and PVDF-HFP-LiTFSI as the solid electrolyte, a solid-state battery was assembled.

[0158] Figure 8 The solid-state battery of Example 8 at 100mA g -1 The cycle performance graph after 800 charge-discharge cycles at a current density is shown. Figure 8 It can be seen that the capacity retention rate is as high as 89% after 800 charge-discharge cycles.

[0159] Example 9: Adding a second active material

[0160] 1. Preparation of cathode material: (1) 0.5g of lithium iron phosphate (LiFePO4, the second active material) with micron-sized sphere microstructure was added to 2mL of 0.1g / mL LiBr (the first active material) methanol solution and stirred magnetically for 12h. Then the mixture was placed in a fume hood until the methanol was completely evaporated. After that, it was dried in a blast oven at 90℃ for 6h. Then the dried solid was ground for later use. In this way, LiBr can fill the pores of LiFePO4 microspheres to form a composite cathode material (LiFePO4 / LiBr).

[0161] (2) Take 0.5g of the above LiFePO4 / LiBr material, mix it into a slurry according to the ratio of 8:1:1 (LiFePO4 / LiBr: conductive carbon black: PVDF), then coat it on the aluminum foil current collector and dry it, and make it into a sheet with a diameter of 11 mm for later use.

[0162] 2. Preparation of half-cell: The half-cell was assembled using the above-mentioned LiFePO4 / LiBr as the positive electrode, lithium metal as the negative electrode, 10mol / L LiFSI propylene carbonate solution as the electrolyte, and glass fiber as the separator. The mass of the positive electrode active material LiBr was 1.0mg and the mass of LiFePO4 was 2.5mg.

[0163] Figure 9 The half-cell of Example 9 at 100 mA g -1 The cycle performance graph after 200 charge-discharge cycles at a current density is shown below. Figure 9 As can be seen, the capacity retention rate is still as high as 98.6% after 200 charge-discharge cycles.

[0164] Example 10: Washing off the template

[0165] Preparation of cathode material: (1) 0.1 g TiO2 nanosheets were added to 100 mL of 0.01 g / mL NaCl methanol and aqueous solution (mixed at a mass ratio of 1:1) and magnetically stirred for 12 h. Then the dispersion was heated to 50 °C until the solvent was completely evaporated. Due to electrostatic interaction, NaCl was partially deposited uniformly on the surface of TiO2 nanosheets in the form of nanoparticles with a particle size of 5-10 nm. Figure 10 a). The solid was then dried in a 90℃ oven for 6 hours. The dried solid was then added to concentrated hydrochloric acid. Since TiO2 nanosheets dissolve in concentrated hydrochloric acid while NaCl does not, the template was etched away, leaving only the low-dimensional NaCl structure. This template removal process does not damage the structure of NaCl, which still partially exhibits a nanoparticle state, and its particle size remains largely unchanged before and after elution. Figure 10(b) This solves the problem of NaCl crystals being difficult to release their capacity. After washing off the template, the obtained NaCl solid was vacuum dried at 90°C for 6 hours, and then the dried solid was ground for later use.

[0166] (2) Repeat step (1) multiple times to obtain 0.5g of the above NaCl solid, mix it into a slurry according to the ratio of 8:1:1 (NaCl: conductive carbon black: PVDF), then coat it on the aluminum foil current collector and dry it, and make it into a sheet with a diameter of 11 mm for later use.

[0167] 2. Preparation of the half-cell: A half-cell was assembled using NaCl as the positive electrode, lithium metal as the negative electrode, a 6 mol / L NaFSI propylene carbonate solution as the electrolyte, and glass fiber as the separator. The mass of the positive electrode active material NaCl was 2.0 mg. This half-cell was tested at 100 mA g. -1 After 500 charge-discharge cycles at a current density, the capacity retention rate is still as high as 91%.

[0168] Comparative Example

[0169] 1. Preparation of positive electrode material: The preparation method of the positive electrode material in this comparative example differs from that in Example 1 in that no carrier is added. Potassium sulfite is directly used as the first active material and mixed with carbon black to prepare the potassium sulfite positive electrode sheet. The steps are as follows: Potassium sulfite, conductive carbon black and PVDF are mixed in a mass ratio of 8:1:1 to form a slurry, which is then coated on an aluminum foil current collector and dried in a drying oven at 100°C for 6 hours to obtain a circular positive electrode sheet with a diameter of 11 mm for later use (where the mass of the active material potassium sulfite is 3 mg).

[0170] 2. Battery assembly: Using the materials from this comparative example as the positive electrode, potassium metal as the negative electrode, and 6 mol / L KFSI ethylene glycol dimethyl ether solution as the electrolyte, a half-cell was assembled and tested.

[0171] Figure 11 The graph shows the cycle performance of the battery in Comparative Example 1 after 100 charge-discharge cycles at 100 mA g. -1 After 100 charge-discharge cycles at a current density of [value missing], the capacity retention was only 39%. The discharge specific capacity of the half-cell in Comparative Example 1 was 105 mAh g. -1 It is only 55% of that in Example 2.

[0172] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a positive electrode material, characterized in that, The preparation method includes: mixing a support and a first active material, and then treating the mixture by high-temperature carbonization or elution to obtain the cathode material; the support is selected from a two-dimensional structure template, or a combination of a two-dimensional structure template and a second active material; the two-dimensional structure template is selected from at least one nanosheet selected from graphene, MXene, and TiO2 nanosheets. The high-temperature carbonization specifically includes: carbonizing the cathode material at a high temperature of 400-1000 °C for 1-10 hours; The elution specifically includes: adding the positive electrode material to the eluent to remove all or part of the template; The first active material is selected from alkali metal halide salts or alkali metal sulfites, alkaline earth metal halide salts or alkaline earth metal sulfites, aluminum halides or aluminum sulfites, or zinc halides or zinc sulfites; the first active material includes low-dimensional structures and / or micro / nano crystals, wherein the low-dimensional structure includes at least one of zero-dimensional structure, one-dimensional structure, two-dimensional structure, three-dimensional structure, and multi-level structure.

2. The preparation method according to claim 1, characterized in that, In the positive electrode material, the first active material is uniformly distributed on the support or in the two-dimensional structure of the support; The two-dimensional structure includes a crystalline structure or an amorphous structure; The template includes zero-dimensional, one-dimensional, or two-dimensional structures; The second active substance has a zero-dimensional structure, a one-dimensional structure, or a two-dimensional structure; The cathode material is at least partially two-dimensional in structure.

3. The preparation method according to claim 1, characterized in that, At least some of the halide salts or sulfites in the cathode material have a zero-dimensional structure, a one-dimensional structure, or a two-dimensional structure. The second active material is selected from LiMn2O4, MnO2, Li3V2(PO4)3, LiFePO4, ternary materials, or Prussian blue-based active materials; The second active substance has nanoparticles, which may or may not be composed of microspheres.

4. The preparation method according to claim 1, characterized in that, The alkali metal halide salt is selected from at least one of lithium chloride, lithium bromide, lithium iodide, sodium chloride, sodium bromide, sodium iodide, potassium chloride, potassium bromide, and potassium iodide. The alkali metal sulfite is selected from at least one of lithium sulfite, sodium sulfite, and potassium sulfite; The alkaline earth metal halide salt is selected from at least one of magnesium chloride, magnesium bromide, magnesium iodide, calcium chloride, calcium bromide, and calcium iodide. The alkaline earth metal sulfite is selected from magnesium sulfite and / or calcium sulfite; The aluminum halide is selected from at least one of aluminum chloride, aluminum bromide, and aluminum iodide; The aluminum sulfite is selected from aluminum sulfite; The zinc halide is selected from at least one of zinc chloride, zinc bromide, zinc iodide, and zinc sulfite; The zinc sulfite is selected from zinc sulfite.

5. The preparation method according to claim 1, characterized in that, In the aforementioned cathode material, the first active material accounts for 1-99% of the total mass of the cathode material; In the aforementioned cathode material, the carrier accounts for 0.1-95% of the total mass of the cathode material; In the carrier, the mass ratio of the template to the second active substance is 0.1-1:0-10.

6. The preparation method according to claim 1, characterized in that, The first active substance has a zero-dimensional structure, a one-dimensional structure, a two-dimensional structure, or a micro / nanocrystalline structure; In the cathode material, when the first active material is distributed in the zero-dimensional structure, one-dimensional structure or two-dimensional structure, the first active material has a zero-dimensional structure, one-dimensional structure or two-dimensional structure. When the first active substance is distributed on the carrier, the first active substance constitutes micro-nano crystals; The particle size range of the micro / nano crystals is 0.1-5 μm; In the cathode material, the content of zero-dimensional structure, one-dimensional structure and two-dimensional structure in the first active material is higher than the content of micro-nano crystals.

7. The preparation method according to claim 1, characterized in that, The cathode material comprises a first active material and a carrier; the carrier comprises a second active material; the first active material and the second active material are combined to form a cathode material; the first active material fills the pores of the nanoparticles or microspheres of the second active material to form a cathode material.

8. The preparation method according to claim 1, characterized in that, The mixture includes: First, mix the template and the first active substance, then add the second active substance; or, First, mix the template and the second active substance, then add the first active substance; or, First, mix the second active substance and the first active substance, and then add the template; In the preparation method, the carrier is pretreated to obtain any form of dispersion, foam, assembled film, powder, or slurry.

9. The preparation method according to claim 1, characterized in that, The method for preparing the cathode material includes the following steps: (A1) The carrier is ultrasonically dispersed in water to obtain a mixture, and the mixture is frozen to obtain foam; (A2) After compacting the foam from step (A1), add a solution containing the first active substance to the compacted foam, and let it dry to obtain the cathode material precursor. (A3) The cathode material precursor obtained in step (A2) is carbonized at high temperature to obtain the cathode material.

10. The preparation method according to claim 9, characterized in that, In the mixture, the mass concentration of the carrier is 1-100 mg / g; The freezing process includes: a first freezing and a second freezing; The conditions for the first freezing include freezing at -70 to -100 °C for at least 1 hour; The conditions for the second freezing include: freeze-drying at -40 to -70 °C for at least 10 hours; Optionally, step (A2) may further include slicing the compacted foam. The solution containing the first active substance comprises the first active substance and a solvent; the solvent is selected from at least one of methanol, ethanol, acetone and dichloromethane; In the solution containing the first active substance, the mass concentration of the first active substance is 0.01-10 g / mL.

11. The preparation method according to claim 1, characterized in that, The method for preparing the cathode material includes the following steps: (B1) The first active substance and the carrier are ultrasonically dispersed in a solvent to obtain a mixture, which is then dried to obtain a solid material; (B2) The solid material from step (B1) is added to the eluent to remove all or part of the template, thereby obtaining an intermediate; (B3) After drying the intermediate from step (B2), the cathode material is obtained; The eluent is selected from concentrated acid or concentrated alkali.

12. The application of the cathode material obtained by the preparation method according to any one of claims 1-11 in a secondary ion battery; The secondary ion battery is selected from organic secondary ion batteries and organic / water hybrid secondary ion batteries.

13. An organic-based secondary ion battery, characterized in that, The organic-based secondary ion battery includes the cathode material obtained by the preparation method according to any one of claims 1-11.

14. The organic secondary ion battery according to claim 13, characterized in that, The organic secondary ion battery further includes a negative electrode material, wherein the negative electrode material is selected from metal and / or carbon negative electrode materials; The metal is selected from at least one of lithium, sodium, potassium, magnesium, calcium, aluminum, and zinc; The carbon anode material is selected from at least one of graphite, hard carbon, and soft carbon.

15. The organic secondary ion battery according to claim 13, characterized in that, The organic secondary ion battery further includes at least one of an electrolyte, a gel electrolyte, or a solid electrolyte, wherein the electrolyte is selected from organic electrolytes; The organic electrolyte comprises an electrolyte and an organic solvent; The electrolyte is selected from at least one of lithium salt, sodium salt, potassium salt, magnesium salt, calcium salt, aluminum salt, and zinc salt; The lithium salt is selected from at least one of lithium sulfate, lithium nitrate, lithium acetate, lithium perchlorate, lithium chloride, lithium difluorosulfonate imide, lithium trifluoromethanesulfonate, lithium bis(trifluoromethanesulfonate)imide, and lithium bis(pentafluoroethylsulfonyl)imide. The sodium salt is selected from at least one of sodium perchlorate, sodium acetate, sodium nitrate, sodium chloride, sodium sulfate, sodium difluorosulfonate imide, sodium trifluoromethanesulfonate, sodium bis(trifluoromethanesulfonate)imide, and sodium bis(pentafluoroethylsulfonyl)imino. The potassium salt is selected from at least one of potassium nitrate, potassium acetate, potassium sulfate, potassium chloride, potassium difluorosulfonate, potassium trifluoromethanesulfonate, potassium bis(trifluoromethanesulfonate)imine, and potassium bis(pentafluoroethylsulfonyl)imine. The zinc salt is selected from at least one of zinc trifluoromethanesulfonate, zinc sulfate, zinc chloride, zinc acetate, zinc trifluoromethanesulfonate, and zinc bis(trifluoromethanesulfonyl)imide; The magnesium salt is selected from at least one of magnesium trifluoromethanesulfonate, magnesium sulfate, magnesium chloride, magnesium acetate, and magnesium bis(trifluoromethanesulfonyl)imide. The organic solvent is selected from at least one of esters, ethers, or nitriles; the ester is selected from at least one of methyl acrylate, diethyl carbonate, or ethylene carbonate. In the organic electrolyte, the concentration of the electrolyte is 0.01-20 mol / L; The gel electrolyte comprises a first polymer host material and an electrolyte, wherein the electrolyte is selected from the organic electrolyte; The first polymer host material is selected from at least one of polyvinyl alcohol, polyacrylic acid, polyacrylamide, sodium polyacrylate, polyethylene oxide, polymethyl methacrylate, polyether ether ketone, ethylene glycol acrylonitrile block copolymer and poly(vinylidene fluoride-hexafluoropropylene); The solid electrolyte is selected from at least one of polymer electrolytes, inorganic solid electrolytes, and composite solid electrolytes; The polymer electrolyte comprises a second polymer matrix and an electrolyte; The second polymer matrix includes at least one of polyethylene oxide, polypropylene oxide, polyvinyl alcohol, polyacrylic acid, polyacrylamide, sodium polyacrylate, polymethyl methacrylate, polyetheretherketone, ethylene glycol acrylonitrile block copolymer, and polyvinylidene fluoride; The inorganic solid electrolyte is selected from at least one of sulfide solid electrolytes and oxide solid electrolytes; The sulfide solid electrolytes include sulfur-lithium ultrafast ion conductors and sulfosilgermanium ore type; The oxide solid electrolyte is selected from at least one of perovskite type, sodium fast ion conductor type, lithium fast ion conductor type and garnet type; The composite electrolyte comprises the polymer electrolyte and a second inorganic filler; the second inorganic filler is selected from TiO2, SiO2, Al2O3, ZrO2, MgO, and ZnO. x Metal oxide nanoparticles and at least one of zeolite and montmorillonite.

16. The organic secondary ion battery according to claim 13, characterized in that, at 500 mA g -1 At a current density of [value missing], the organic secondary ion battery retains more than 73% of its capacity after 600 charge-discharge cycles; or, at 100 mA g -1 At a given current density, the organic secondary ion battery retains more than 88% of its capacity after 600 charge-discharge cycles.

17. An organic / water hybrid secondary ion battery, wherein the organic / water hybrid secondary ion battery comprises a positive electrode material obtained by the preparation method according to any one of claims 1-11.

18. The organic / water hybrid secondary ion battery according to claim 17, characterized in that, The organic / water hybrid secondary ion battery includes a hybrid electrolyte, a positive electrode material, and a negative electrode material. The hybrid electrolyte includes an electrolyte and a mixed solvent of an organic solvent and water, wherein the electrolyte has the meaning as described in claim 15; and the negative electrode material has the meaning as described in claim 14.

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